The invention relates to a clamping device for power cables which serves to connect a power cable to an X-ray tube or to high-voltage equipment.
As a rule, with known power cables which are used in X-ray units, resetting is repeatedly required after the first insertion into the corresponding cone of an X-ray tube or of a generator. This is because the contact pressure exerted on the rubber cone used as connection element eases because of the change in the mechanical properties of the rubber cone. The natural rubber used for the rubber cone settles over time, and surplus quantities of silicone on the so-called junction are expelled. When there is no longer a form-locking fit of the rubber cone to the insulator, high-voltage spark-overs, which can lead to the destruction of the power cable and of the X-ray tube or of the generator, occur inside the junction. The pressure path can be monitored only by opening the connection, which leads to a very high maintenance outlay, in particular also because of the necessary shutdown of the whole X-ray unit during this time.
Maintenance-free fixed connections between the power cable and a mating connector have therefore been proposed. The rubber cone of the power cable is vulcanized into the mating connector of the tube and set under extremely high pressure. However, a disadvantage of this is that the X-ray tube and the power cable form a unit which must be replaced together when servicing takes place, which means higher logistical and storage costs. This is the case in particular when different cable lengths are required.
In addition it is known from U.S. Pat. No. 6,556,654 B1 to provide a low-maintenance bent power cable with a pressure spring which is integrated into the cable flange. In the area of the pressure spring, a mechanical pointer is fitted which makes it possible, by reading off a position—which corresponds to the spring excursion—to verify the status of the quality of the high-voltage connection without opening the connection. Such a solution does not work, however, for the standard cables used in the industrial X-ray field.